This invention relates to a metal terminal for a wedge-base bulb (baseless bulb).
FIGS. 5 to 7 show a common wedge-base bulb (hereinafter referred to as "bulb") and conventional metal terminals for a wedge-base bulb.
The bulb 10 comprises a hollow light-emitting portion 11 of a generally cylindrical shape, and a flat plate-like base portion 12 formed at a lower end of the light-emitting portion 11. Lead wires 13, received in the light-emitting portion 11, are extended outwardly respectively from opposite end portions of a bottom surface 12A of the base portion 12, and these outwardly-extended portions are folded respectively on holding surfaces 12B and 12B of the base portion 12, facing away from each other, to form contacts arranged in a point-symmetrical manner. A retaining groove 14 is formed in an upper portion of each of the holding surfaces 12B, and extends in a horizontal direction.
The conventional metal terminal 1 includes a pair of holder pieces 2 and 2 which can hold the base portion 12 therebetween, and are symmetrical in shape. Each of the holder pieces 2 and 2 has a retaining projection 3 formed at a distal end thereof, and the two retaining projections 3 and 3 are curved or projected toward each other. When the base portion 12 is inserted between the holder pieces 2 and 2, the retaining projections 3 are engaged respectively in the retaining grooves 14 in the base portion 12 to thereby retain the bulb 10 against withdrawal, and at the same time one of the holder pieces 2 is held against the lead wire 13, and hence is electrically connected thereto. The above-mentioned metal terminal 1 is disclosed, for example, in the Unexamined Japanese Utility Model Application Publication No. Hei 2-82887.
Each lead wire 13 is extended outwardly from the bottom surface 12A of the base portion 12, and is folded upwardly to be merely laid on the holding surface 12B. Therefore, in some cases, the distal end portion of the lead wire 13 is displaced to be tilted, as shown in FIG. 7. As a result, in the conventional metal terminal 1, the lead wire 13 is received in a recessed portion of the holder piece 2, which is closer to the proximal end of the holder piece 2 than the retaining projection 3 is, and this results in a problem that the holder piece 2 fails to be held against the lead wire 3, thus causing a contact failure.